#body {
    margin: auto;
    position: absolute;
    left: 50%;
    padding-top: 40%;
    transform: translateX(-50%) translateY(-50%);
    text-align: center;
}

#title {
    font-size: 3rem;
}

@media screen and (max-width:680px) {
    #body {
        top: 40%;
    }
    #title {
        font-size: 2rem;
    }
}